66667440 has 120 divisors (see below), whose sum is σ = 240453360. Its totient is φ = 15235584.

The previous prime is 66667429. The next prime is 66667441. The reversal of 66667440 is 4476666.

It is a tau number, because it is divible by the number of its divisors (120).

It is not an unprimeable number, because it can be changed into a prime (66667441) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8926 + ... + 14594.

It is an arithmetic number, because the mean of its divisors is an integer number (2003778).

Almost surely, 2^66667440 is an apocalyptic number.

66667440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66667440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120226680).

66667440 is an abundant number, since it is smaller than the sum of its proper divisors (173785920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66667440 is a wasteful number, since it uses less digits than its factorization.

66667440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5699 (or 5686 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 39.

The square root of 66667440 is about 8165.0131659416. The cubic root of 66667440 is about 405.4817008887.

The spelling of 66667440 in words is "sixty-six million, six hundred sixty-seven thousand, four hundred forty".